Parts such as the Carburetor: Tube, Spring, Piston, Jet,main(#140), Screw-wash.,4x12 are included in the Ft500 Ascot 1983 (d) Usa Carburetor parts fiche.
This Carburetor Assy. is the most expensive of the items that make up this Carburetor assembly.
On this parts fiche the Screw-wash.,4x12 is the most specified component.